| 书目名称 | New Challenges in Superconductivity: Experimental Advances and Emerging Theories | | 副标题 | Proceedings of the N | | 编辑 | J. Ashkenazi,Mikhail V. Eremin,Fulin Zuo | | 视频video | | | 丛书名称 | NATO Science Series II: Mathematics, Physics and Chemistry | | 图书封面 |  | | 描述 | This volume contains the proceedings of the 2004 University of Miami Workshop on Unconventional Superconductivity. The workshop was the fourth in a series of successful meetings on High-T Superconductivity and C related topics, which took place at the James L. Knight Physics Building on the University of Miami campus in Coral Gables, Florida, in January 1991, 1995, 1999, and 2004. The workshop consisted of two consecutive events: 1. NATO Advanced Research Workshop (ARW) on New Challenges in Superconductivity: Experimental Advances and Emerging Theories, held on January 11-14, 2004; 2. Symposium on Emerging Mechanisms for High Temperature Superconductivity (SEMHTS), held on January 15-16, 2004. It is hard to write a balanced preface to a volume like this one, yet at least we try to offer the reader a taste of what was happening in this workshop. There were close to a hundred scientists from around the world, albeit fewer Russians than we had originally hoped for. Nevertheless, the workshop was very lively and we trust that this is demonstrated in this volume. The workshop included high-quality presentations on state of the art works, yet a key issue, discussed by many, was how homog | | 出版日期 | Conference proceedings 2005 | | 关键词 | Doping; HTS; High-temperature superconductivity; NMR; Superconductor; magnetism | | 版次 | 1 | | doi | https://doi.org/10.1007/1-4020-3085-1 | | isbn_softcover | 978-1-4020-3084-0 | | isbn_ebook | 978-1-4020-3085-7Series ISSN 1568-2609 | | issn_series | 1568-2609 | | copyright | The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature B.V. 200 |
| 1 |
Front Matter |
|
|
Abstract
|
| 2 |
,Lattice Dynamics and Electron Pairing in High Temperature Superconductors, |
A. Lanzara,G.-H. Gweon,S. Y. Zhou |
|
Abstract
Angle resolved photoemission spectroscopy combined with isotope substitution (.O→.O) sample preparation method is used to probe the effect of the lattice degrees of freedom on the electron dynamics of optimally doped Bi.Sr.CaC.O. high temperature superconductors, as a function of momentum and temperature. Our data show that the lattice dynamics strongly renormalizes the electron dispersion and the photoemission line shapes. The renormalization is enhanced near the anti-nodal region and in the superconducting state, i.e. as the superconducting gap opens up. This unusual behavior is direct evidence that the electron-phonon interaction is correlated with the electron pairing in the high temperature superconductivity.
|
| 3 |
,Direct Arpes and TC Enhancement in Compressively Strained LSCO-214 Films, |
Davor Pavuna,Mike Abrecht,Daniel Ariosa,Dominique Cloetta |
|
Abstract
Direct ARPES studies on . grown strained LSCO-214 films show striking strain effects on the electronic structure. The Fermi surface (FS) of LSCO-214 evolves with doping, yet changes even more significantly with strain. The compressive strain changes the Fermi surface topology from hole-like to electron-like and causes band dispersion along k. and the Fermi level crossing before the Brillouin zone boundary, in sharp contrast to the ‘usual’ flat band remaining ≈30meV below E. measured on unstrained samples. The associated reduction of the density of states does not diminish the superconductivity; rather, T. is strongly enhanced (up to factor of two) in compressively strained thin films.
|
| 4 |
,Full Fermi Surface of a High Temperature Superconductor Revealed by Angular Magnetoresistance Oscil |
N. E. Hussey,M. Abdel-Jawad,A. Carrington,A. P. Mackenzie,L. Balicas |
|
Abstract
We report the first observation of polar angular magnetoresistance oscillations in the high-. cuprate Tl.Ba.CuO.. These measurements establish the existence of a coherent three-dimensional Fermi surface on the overdoped, superconducting side of the cuprate phase diagram, even in materials with extreme electrical anisotropy. Detailed analysis of the oscillations reveals that .-axis dispersion vanishes at specific symmetry points. This observation has implications for our understanding of a wide range of unusual metallic and superconducting properties of cuprates.
|
| 5 |
,Sum Rules and Energy Scales in BiSrCaCuO, |
A.F. Santander-Syro,R.P.S.M. Lobo,N. Bontemps |
|
Abstract
From very high accuracy reflectivity spectra, we have derived the optical conductivity and estimated the spectral weight up to various cut-off frequencies in underdoped Bi.Sr.CaCu.O. (Bi-2212). We show that, when evaluating the optical spectral weight over the full conduction band (1 eV), the kinetic energy decreases in the superconducting state, unlike in conventional BCS superconductors. As a consequence, the Ferrell-Glover-Tinkham sum rule is not satisfied up to this energy scale. This stands as a very unconventional behavior, contrasted with the overdoped Bi-2212 sample.
|
| 6 |
,Optical Properties of (Pr,Ce)2CuO4, |
A. Zimmers,N. Bontemps,R.P.S.M. Lobo,C.P. Hill,M.C. Barr,R.L. Greene,C.C. Homes,A.J. Millis |
|
Abstract
We studied the optical conductivity of electron doped Pr.Ce.CuO. from the underdoped to the overdoped regime. The observation of low to high frequency spectral weight transfer reveals the presence of a gap, except in the overdoped regime. A Drude peak at all temperatures shows the partial nature of this gap. The close proximity of the doping at which the gap vanishes to the antiferromagnetic phase boundary leads us to assign this partial gap to a spin density wave.
|
| 7 |
,Tunneling Spectra Near , Inoverdoped Bi,Sr,CaCu,O, |
M. Oda,Y. Tanaka,A. Hashimoto,N. Momono,M. Ido |
|
Abstract
In this article, we focus on the dip structure of tunneling spectra in overdoped Bi.Sr.CaCu.O. (Bi2212), measured in Bi2212/vaccum/Bi2212 junctions, which are of the superconductor/insulator/superconductor (SIS) type below .. It is confirmed that the dip structure appears at voltages |.| ∼ (2Δ.+.)/. in the SIS type tunneling spectra, where 2Δ. is twice the d-wave superconducting (SC) gap amplitude and . the energy of an antiferromagnetic (AF) resonance mode. Furthermore, it is demonstrated that the temperature evolution of the dip structure is in good agreement with that of the AF resonance mode, which also develops below .. These results suggest that the tunneling dip structure will be associated with the development of AF resonance mode in accordance with the SC transition.
|
| 8 |
,Andreev — Saint James Reflections as a Tool for the Study of Unconventional Superconductors, |
Guy Deutscher |
|
Abstract
Andreev — Saint James reflections have been observed at normal metal contacts and tunnel junctions with YBCO, LSCO, BSCCO and other High Temperature Superconductors. The characteristic feature of these reflections is an enhanced conductance at low bias. Its observation implies the existence of extended quasiparticle arcs around the nodal directions. The enhancement persists up to Tc and so far has not been observed above it. Return to the normal state conductance occurs at an energy that scales with Tc, including in the pseudogap regime. In YBCO, the detailed shape of the conductance at low bias is consistent with a pure d-wave symmetry of the order parameter in the optimally doped and underdoped regimes, and with a mixed symmetry in the overdoped one.
|
| 9 |
,Bi,Sr,CaCu,O, ,-Axis Bicrystal Twist and Cross-Whisker Experiments, |
Richard A. Klemm |
|
Abstract
The combined bicrystal, artificial cross-whisker, and natural cross-whisk. .-axis twist experiments on Bi.Sr.CaCu.O. (Bi2212) provide strong evidence that the superconducting order parameter is predominantly ._wave for . ≤ ., and that the .-axis tunneling is strongly incoherent.
|
| 10 |
,Nodeless Pairing State in YBa2Cu3O7, |
Dale R. Harshman,John D. Dow,W. J. Kossler,A. T. Fiory,A. J. Greer,D. R. Noakes,C. E. Stronach,E. Ko |
|
Abstract
Muon spin rotation (.SR) results are reported on single-crystal YBa.Cu.O., having a transition temperature of T. = 91.3 K with ΔT. < 0.5 K (in zero applied field). Flux motion and de-pinning can mask intrinsic properties such as the true underlying pairing state, and has led to misinterpretations of data. The present data exhibit a non-monotonic behavior for the second moment of the internal field distribution as a function of field as T→0, which rules out any single pairing state explanation of the data, without including other . effects. The data are, however, consistent with .-wave (or extended .-wave) pairing, provided that field-dependent and temperature-activated vortex de-pinning are first taken into account. Applying a self-consistent vortex de-pinning model, the data are found to be best described by an underlying two-fluid model, yielding a London penetration depth value of λ.(T=0,H=0) = 127.6 nm. Attempts to fit the data using BCS theory with varying coupling strengths and a .-wave model produced much poorer fits. In fact, the probability that the .-wave model gives a better fit than the two-fluid model is less that 4×10.. This work reveals that the .-wave interpretation
|
| 11 |
,Nuclear Spin Relaxation and Incommensurate Magnetism in Doped Cuprates, |
L. P. Gor’kov,G. B. Teitel’baum |
|
Abstract
Existing data on .Cu-nuclear spin relaxation reveal two independent relaxation processes: the one that is temperature independent we link to incommensurate peaks seen by neutrons, while the “universal” temperature dependent contribution coincides with 1/.(.) for two-chain YBCO 124. We argue that this new result substitutes for a “pseudogap” regime in a broad class of high-. cuprates and stems from the 1st order phase transition that starts well above the superconductivity . but becomes frustrated because of broken electroneutrality in the CuO. plane.
|
| 12 |
,Antiferromagnetic Vortex Core in Htsc Studied by Spatially-Resolved NMR, |
K. Kumagai,K. Kakuyanagi,Y. Matsuda,M. Hasegawa |
|
Abstract
Spatially-resolved NMR is used to probe antiferromagnetism in the vortex state of nearly optimally doped high-. cuprate Tl.Ba.CuO. (. = 85 K). The broadened .Tl-spectra below 20 K and the temperature dependence of the enhanced nuclear spin-lattice relaxation rate . at the vortex core region indicate clear evidences of the antiferromagnetic order inside the vortex core of Tl.Ba.CuO..
|
| 13 |
,Exploring the Oxygen Order in Hg -1223 and Hg -1201 by 199Hg Mas Nmr, |
Raivo Stern,Ivo Heinmaa,Dmitriy A. Pavlov,Ingrid Bryntse |
|
Abstract
We demonstrate the use of a high-resolution solid-state fast (45 kHz) magic angle spinning (MAS) NMR for mapping the oxygen distribution in Hg-based cuprate superconductors. We identify observed three peaks in .Hg spectrum as belonging to the different chemical environments in the HgO. layer with no oxygen neighbors, single oxygen neighbor, and two oxygen neighbors. We discuss observed differences between Hg-1201 and Hg-1223 materials.
|
| 14 |
,Two Fluids Formation in the Normal State of High-, Superconductor, |
J. S. Kim,Y. W. Park |
|
Abstract
Thermoelectric power (TEP) of high-. superconductors has been investigated in a wide range of temperature (. < . < 700 K) for La.Sr.CuO.. For wide doping level from underdoping to heavily overdoping, TEP follows the linear-. dependence above the broad peak temperature, .. At high temperatures, however, TEP shows deviation from the linear-. dependence at a certain temperature ., which is consistent with the pseudogap temperature. The systematic change of the TEP behavior is discussed in terms of the two fluids model of bound pairs and independent normal carriers.
|
| 15 |
,Temperature Dependence of In-Plane Resistivity of Ybco, |
J. Jung,M. Abdelhadi |
|
Abstract
Variation of the magnitude and the temperature dependence of the normal state resistivity .(.) has been very frequently observed in different . (YBCO) single crystals (or YBCO thin films) of the same .. We investigated the origin of these changes by analyzing optimally doped and underdoped YBCO thin films (with 7−. = 6.80−6.95) whose resistivity .(.) was characterized by a “superlinear” temperature dependence [with a flattening of .(.) below 230K]. We induced oxygen redistribution in these films without any change in the total oxygen content, by either careful annealing over a temperature range of 120–140°. in argon, or by aging at room temperature in air. This procedure leads to a transition from a superlinear .(.) towards the linear one, and an increase of both the magnitude of resistivity and .. Long-term aging yields a perfectly linear .(.). We proposed a filamentary model of the changes in .(.), which is based on a thermally activated redistribution of the interchain bridging oxygen O(5) in the chain-layer of YBCO. The results show that a perfectly linear .(.) can be observed in YBCO of oxygen content 7−. as low as 6.8, which is essential for the development of theories of the
|
| 16 |
,Measurements of the Doping Effects on the In-Plane Paraconductivity in Cuprate Superconductors, |
Felix Vidal,Manuel V. Ramallo,Gonzalo Ferro,Jose Antonio Veira |
|
Abstract
We will summarize here some of our measurements of the superconducting fluctuations effects on the in-plane electrical resistivity (the so-called in-plane paraconductivity) in La.Sr.CuO. thin films with different Sr content. Our results suggest that these superconducting fluctuations effects are not related to the opening of a pseudogap in the normal-state of underdoped compounds.
|
| 17 |
,A Possibility of a Phase Fluctuationlike Effect in Htsc Cuprates, |
Yu. S. Nechaev |
|
Abstract
On the basis of the thermodynamic analysis of the related experimental data, a possibility is shown of a manifestation of a phase fluctuation-like effect in the high-temperature superconducting (HTSC) cuprates, especially with respect to physical properties of melt-textured composites, thin films, coatings, nanomaterials and heterostructures.
|
| 18 |
,Pseudogap Behavior in Underdoped Cuprates, |
David Pines |
|
Abstract
I review some of the experimental evidence and theoretical arguments that suggest that pseudogap matter is a new form of matter that coexists with coherent electron matter in the normal state and with superconducting matter below the superconducting transition temperature. I describe work in progress on a phenomenological two-fluid description of the evolution of pseudogap behavior that offers an explanation for the unexpectedly simple scaling behavior for the uniform magnetic susceptibility found in the underdoped cuprates and use this to propose a physical picture of the underdoped cuprates and to estimate the fraction of quasiparticles that become superconducting in underdoped superconductors.
|
| 19 |
,Notes on Rvb-Vanilla by Anderson et al., |
C.M. Varma |
|
Abstract
The claims made for the Resonating Valence Bond ideas for the Cuprates in a recent paper by Anderson et al. on the basis of a variational calculation are discussed.
|
| 20 |
,Enhanced Tc Near the Metal/Insulator Transition: A New Perspective on Unconventional Superconductin |
M. S. Osofsky,R. J. Soulen Jr. |
|
Abstract
Many apparently unrelated systems, including disordered metals and metallic oxides, undergo a metal/insulator transition (MIT) when their carrier concentrations are reduced and/or their disorder is increased. We have found that the superconducting transition temperature, T., of such materials is very often enhanced in the vicinity of the MIT. We have constructed superconductivity phase diagrams (T. vs σ, the conductivity) for many materials whose only common feature is proximity to the MIT and found that they are remarkably similar.
|
|
|
发表于 2025-3-21 18:02:40
